Go Language Interview Questions

Checkout Vskills Interview questions with answers in Go Language to prepare for your next job role. The questions are submitted by professionals to help you to prepare for the Interview.    

Q.1 What is the go get command, and how is it used?
go get is a command to download and install external packages from remote repositories. It's commonly used to fetch dependencies.
Q.2 Explain how interfaces work in Go.
An interface defines a set of method signatures. A type implicitly implements an interface if it provides all the methods defined by that interface.
Q.3 How do you create a custom error type in Go?
You can create a custom error type by implementing the Error() method on a struct and having it return an error message.
Q.4 What is the difference between nil and null in Go?
In Go, nil is used to represent a zero or empty value for pointers, slices, maps, channels, and interfaces. Go does not have a concept of null for most other types.
Q.5 Explain the concept of type assertions in Go.
Type assertions are used to extract the underlying value from an interface. They check if an interface value is of a certain type and, if so, return that value.
Q.6 What is the purpose of the range keyword in Go?
range is used in loops to iterate over elements in slices, arrays, maps, and channels. It simplifies iteration and provides both the index and value.
Q.7 How do you handle concurrent access to shared data in Go?
You can use mutexes or channels to synchronize access to shared data and prevent race conditions in concurrent programs.
Q.8 What is the difference between shallow and deep copying?
Shallow copying duplicates only the references, while deep copying duplicates the entire data structure, including nested objects. Go performs shallow copying by default.
Q.9 Explain the purpose of the sync package in Go.
The sync package provides synchronization primitives like mutexes and wait groups for managing concurrent access to shared resources.
Q.10 How do you define constants in Go?
Constants in Go are declared using the const keyword and must have a known value at compile-time. They can be of various types, including numeric and string constants.
Q.11 What are slices, and how do they differ from arrays in Go?
Slices are dynamically sized and reference a portion of an array. They are more flexible than arrays, which have a fixed size. Slices do not store data; they point to it.
Q.12 Explain the difference between a method and a function in Go.
A method is a function associated with a type, while a function is a standalone block of code. Methods can access and modify the fields of the associated type.
Q.13 What is the purpose of the new keyword in Go?
The new keyword is used to create a new instance of a value type and returns a pointer to that value. It allocates memory and initializes the fields to their zero values.
Q.14 How do you handle errors returned by functions in Go?
You typically check the returned error value using conditional statements, and if an error occurs, you handle it accordingly, such as logging or returning it.
Q.15 Explain how defer statements work with functions in Go.
A defer statement schedules a function call to run when the surrounding function exits, regardless of how it exits (e.g., return, panic, normal exit).
Q.16 What is the zero value in Go, and how is it determined?
The zero value is the default value assigned to variables if no initial value is provided. It is determined based on the data type, such as 0 for integers and an empty string for strings.
Q.17 How do you concatenate strings in Go?
You can use the + operator or the fmt.Sprintf function to concatenate strings in Go. Strings are immutable, so concatenation creates a new string.
Q.18 Explain the use of the break and continue statements in Go.
break is used to exit a loop prematurely, and continue is used to skip the current iteration and move to the next one in a loop.
Q.19 What is the purpose of the select statement in Go?
The select statement is used for concurrent communication with channels. It allows a goroutine to wait on multiple channels for data or events.
Q.20 How do you remove an element from a slice in Go?
You can remove an element from a slice by creating a new slice with the undesired element omitted, typically using slicing and append operations.
Q.21 What is a rune in Go, and how is it different from a string?
A rune is a 32-bit integer representing a Unicode character. It differs from a string, which is a sequence of bytes. Runes are used for character manipulation.
Q.22 Explain the purpose of the interface{} type in Go.
interface{} is the empty interface type, and it can hold values of any type. It is often used when you need to work with values of unknown types, such as in generic programming.
Q.23 How do you convert between different numeric types in Go?
You can convert between numeric types by explicitly casting them, like int32(myInt) to convert an int to int32.
Q.24 What is the purpose of the range keyword in for loops?
The range keyword is used in for loops to iterate over elements in collections like slices, arrays, maps, and channels. It simplifies iteration.
Q.25 Explain how to use the sync.Mutex type for synchronization.
sync.Mutex is used to create a mutual exclusion lock. You can lock and unlock it to protect shared resources from concurrent access.
Q.26 How do you handle panics and recover from them in Go?
You use panic to raise an exception, and you can recover from it using the recover function within a deferred function. This allows for controlled error handling.
Q.27 What is the purpose of the go build command in Go?
go build is used to compile Go source code into executable binary files or libraries. It also checks dependencies and updates them if necessary.
Q.28 How does Go handle dependency management?
Go uses a dependency management tool called go get and a go.mod file to manage and version dependencies. The go.sum file ensures secure downloads.
Q.29 Explain the concept of goroutine scheduling in Go.
Go's scheduler, called the Goroutine Scheduler, manages the execution of goroutines. It allocates processor time to them in an efficient manner, minimizing blocking.
Q.30 What is the purpose of the defer statement in Go?
The defer statement is used to schedule a function call to run when the surrounding function exits, ensuring cleanup tasks are performed.
Q.31 What is the difference between a pointer receiver and a value receiver in Go?
A pointer receiver allows a method to modify the receiver's value, while a value receiver works on a copy and cannot modify the original value.
Q.32 Explain the purpose of the json package in Go.
The json package in Go is used for encoding and decoding JSON data. It allows Go structs to be converted to JSON and vice versa.
Q.33 How do you handle concurrent access to shared resources in Go?
You can use synchronization primitives like mutexes, channels, and the sync package to safely access shared resources in a concurrent program.
Q.34 What is the purpose of the close function in Go channels?
The close function is used to close a channel, indicating that no more data will be sent on it. It can be used to signal the end of communication.
Q.35 How does Go handle memory management and garbage collection?
Go uses a garbage collector to automatically manage memory by reclaiming objects that are no longer in use. It runs concurrently to minimize pauses.
Q.36 What is a callback function, and how is it used in Go?
A callback function is a function passed as an argument to another function. In Go, you can pass functions as values and invoke them at a later time.
Q.37 Explain the concept of a slice header in Go.
A slice header is a data structure that contains information about a slice, including a pointer to its underlying array, its length, and its capacity.
Q.38 What is the GOPATH environment variable in Go, and how is it used?
GOPATH is an environment variable that specifies the workspace for Go projects. It contains directories for source code, binaries, and dependencies.
Q.39 Explain the sync.WaitGroup type in Go and its purpose.
sync.WaitGroup is used for waiting for a collection of goroutines to finish their execution. It allows you to block until all goroutines have completed.
Q.40 How do you implement a simple HTTP server in Go?
You can create an HTTP server in Go using the http package. You define request handlers, listen on a port, and use the http.ListenAndServe function.
Q.41 What is the purpose of the init function in Go?
The init function is used for package initialization. It is automatically called before the main function when a package is imported.
Q.42 Explain the concept of method chaining in Go.
Method chaining allows you to call multiple methods on an object in a single line by returning the object itself from each method. It improves code readability.
Q.43 How do you handle file I/O in Go?
Go provides the os and io/ioutil packages for file I/O. You can use functions like os.Open, ioutil.ReadFile, and os.Create to work with files.
Q.44 What is the purpose of the context package in Go?
The context package is used for managing cancellation, deadlines, and timeouts in Go applications, making it easier to handle long-running operations.
Q.45 Explain how to create and use custom packages in Go.
To create a custom package, you organize your Go files into a directory and define a package name in each file. You can then import and use the package in other code.
Q.46 Is Go better than Python?
On most benchmarks, Go beats Python by far. Go even beats Java's speed, which is widely considered to be significantly faster than Python. If it comes down to needing a program to load software quickly, Go is the way to Go.
Q.47 How do you work with command-line arguments in Go?
You can access command-line arguments using the os.Args variable. It provides a slice of strings, with the first element being the program's name.
Q.48 What do you understand by packages in Go program?
The purpose of a package is to design and maintain a large number of programs by grouping related features together into single units so that they can be easy to maintain and understand and independent of the other package programs.
Q.49 What is the difference between a shallow copy and a deep copy in Go?
A shallow copy duplicates references to data, while a deep copy duplicates the data itself, including nested objects. Go's assignment and slicing perform shallow copying.
Q.50 What is Pkg in Golang?
The pkg directory contains Go package objects compiled from src directory Go source code packages, which are then used, at link time, to create the complete Go executable binary in the bin directory. We can compile a package once, but link that object into many executables.
Q.51 Explain the concept of method receivers in Go.
Method receivers specify which types can call a method. They can be of two types: value receivers (for values) and pointer receivers (for pointers).
Q.52 Where are Go packages installed?
The packages from the standard library are available at the “pkg” subdirectory of the GOROOT directory. When you install Go, an environment variable GOROOT will be automatically added to your system for specifying the Go installer directory.
Q.53 What is a variadic parameter, and how is it defined in Go?
A variadic parameter is a parameter that can accept a variable number of arguments. In Go, you define it using ... before the parameter type, such as func myFunc(args ...int).
Q.54 Does Go support generic programming
Go already supports a form of generic programming via the use of empty interface types. For example, we can write a single function that works for different slice types by using an empty interface type with type assertions and type switches.
Q.55 How does Go handle exception handling compared to languages like Java?
Go uses a panic-recover mechanism for error handling instead of traditional exceptions. It encourages explicit error checking and handling.
Q.56 Does Go support inheritance or generics?
Go does not support inheritance, however, it does support composition. The generic definition of composition is "put together".
Q.57 Explain the copy function in Go and its usage.
The copy function is used to copy elements from one slice to another. It ensures that the destination slice has enough capacity and returns the number of elements copied.
Q.58 Does Golang support inheritance?
Since Golang does not support classes, so inheritance takes place through struct embedding. We cannot directly extend structs but rather use a concept called composition where the struct is used to form other objects. So, you can say there is No Inheritance Concept in Golang.
Q.59 What is the purpose of the interface type in Go?
The interface type defines a set of method signatures. Types that implement these methods implicitly satisfy the interface, allowing polymorphism and abstraction.
Q.60 Why there are no classes in Golang?
Basically Go doesn't have the keyword, “class ” unlike other object-oriented languages like C++/Java/Python, etc… but (here comes the exception!!!) The only difference in a normal struct and an implicit class is that struct is defined by the programmer and then passed on to a function or a method and then processed.
Q.61 How do you check if a value implements an interface in Go?
You can use type assertion to check if a value implements an interface. If the assertion succeeds, you can access the methods defined in that interface.
Q.62 Does Golang support abstraction?
Golang is quite capable of implementing higher level abstractions. You can use interfaces to create common abstraction that can be used by multiple types.
Q.63 What are defer, panic, and recover used for in Go error handling?
Defer is used for cleanup tasks, panic is used to raise an exception, and recover is used to handle and possibly resume from a panic. They work together for controlled error handling.
Q.64 Is Go a case sensitive language
The Go Language is case sensitive
Q.65 Explain how goroutines are scheduled and managed in Go.
Goroutines are scheduled by the Go runtime using a lightweight threading model. The scheduler multiplexes them onto OS threads and handles their execution.
Q.66 What do you understand by a string literal in Go programming
A string literal represents a string constant obtained from concatenating a sequence of characters. There are two forms: raw string literals and interpreted string literals. Raw string literals are character sequences between back quotes, as in `foo` . Within the quotes, any character may appear except back quote.
Q.67 What is a select statement in Go, and how is it used?
A select statement is used for concurrent communication with channels. It allows you to wait on multiple channels for data or events and execute the corresponding case.
Q.68 Where is Go workspace?
The GOPATH environment variable specifies the location of your workspace. It defaults to a directory named go inside your home directory, so $HOME/go on Unix, $home/go on Plan 9, and %USERPROFILE%\go (usually C:\Users\YourName\go ) on Windows.
Q.69 How do you handle timeouts in Go for blocking operations?
You can use the time.After function in combination with a select statement to implement timeouts for blocking operations.
Q.70 What is the default value of type bool in Go programming?
The default value for the bool type in the Go programming language is false.
Q.71 What is the purpose of the sync.Cond type in Go?
sync.Cond is used for conditional variable synchronization. It allows goroutines to wait until a certain condition is met before proceeding.
Q.72 What is GOPATH environment variable in go programming?
The GOPATH environment variable specifies the location of your workspace. It defaults to a directory named go inside your home directory, so $HOME/go on Unix, $home/go on Plan 9, and %USERPROFILE%\go (usually C:\Users\YourName\go ) on Windows.
Q.73 Explain the use of context in Go for handling timeouts and cancellations.
The context package in Go is used for managing timeouts, deadlines, and cancellations in long-running operations. It enables graceful termination and cleanup.
Q.74 What are the several built-in supports in Go?
A list of built-in supports in Go: Container: container/list, container/heap. Web Server: net/http. Cryptography: Crypto/md5 ,crypto/sha1.
Q.75 What is the purpose of the cgo tool in Go, and when is it used?
cgo is used to call C code from Go and vice versa. It allows Go programs to interact with existing C libraries and systems.
Q.76 What do you understand by goroutine in Go programming language?
A Goroutine is a function or method which executes independently and simultaneously in connection with any other Goroutines present in your program. Or in other words, every concurrently executing activity in Go language is known as a Goroutines.
Q.77 Why do we need Goroutine?
Goroutines are functions or methods that run concurrently with other functions or methods. Goroutines can be thought of as lightweight threads. The cost of creating a Goroutine is tiny when compared to a thread. Hence it's common for Go applications to have thousands of Goroutines running concurrently.
Q.78 What are threads in Golang?
A thread is a lightweight process, or in other words, a thread is a unit which executes the code under the program. So every program has logic and a thread is responsible for executing this logic. Goroutines are managed by the go runtime. Operating system threads are managed by kernel.
Q.79 Is a Goroutine a thread?
A goroutine isn't a thread: it's merely a function executed in a thread that is dedicated a chunk of stack space. If your process have more than one thread, this function can be executed by either thread.
Q.80 Is Go concurrent or parallel?
Goroutines are concurrent and, to an extent, parallel; however, we should think of them as being concurrent. The order of execution of goroutines is not predictable and we should not rely on them to be executed in any particular order.
Q.81 What are channels in Go?
In Golang, or Go, channels are a means through which different goroutines communicate. They are similar to pipes through which you can connect with different concurrent goroutines. The communication is bidirectional by default, meaning that you can send and receive values from the same channel.
Q.82 Is Golang multi threaded?
The Go standard library also uses goroutines where ever possible. With Go, it's possible to do multi-threaded concurrency and parallelization with goroutines and goroutines work in an asynchronous way hence making use of both multi-threading and asynchronous programming efficiently.
Q.83 Is Golang parallelism?
Golang offers a specific CSP (Communication Sequential Processes) paradigm in its base, which allows for convenient parallel processing using Goroutines to facilitate concurrent execution in code.
Q.84 How to write multiple strings in Go programming
Creating a multiline string in Go is actually incredibly easy. Simply use the backtick ( ` ) character when declaring or assigning your string value. str := `This is a multiline string.
Q.85 What do you understand by a pointer in Go?
Pointers in Go programming language or Golang is a variable that is used to store the memory address of another variable. Pointers in Golang is also termed as the special variables. The variables are used to store some data at a particular memory address in the system.
Q.86 What do you understand by Go Interfaces
An interface in Go is a type defined using a set of method signatures. The interface defines the behavior for similar type of objects. An interface is declared using the type keyword, followed by the name of the interface and the keyword interface . Then, we specify a set of method signatures inside curly braces.
Q.87 What are methods in Go?
Go methods are similar to Go function with one difference, i.e., the method contains a receiver argument in it. With the help of the receiver argument, the method can access the properties of the receiver. Here, the receiver can be of struct type or non-struct type.
Q.88 What is wait group golang?
WaitGroup is actually a type of counter which blocks the execution of function (or might say A goroutine) until its internal counter become 0.
Q.89 What is type assertion in Golang?
Type assertions in Golang provide access to the exact type of variable of an interface. If already the data type is present in the interface, then it will retrieve the actual data type value held by the interface. A type assertion takes an interface value and extracts from it a value of the specified explicit type.
Q.90 What is the default value of a variable in Go?
Local and global variables are initialized to their default value, which is 0; while pointers are initialized to nil.
Q.91 What is Go (Golang), and why was it created?
Go, also known as Golang, is a statically typed, compiled programming language developed at Google. It was created to address issues in existing languages, focusing on simplicity and efficiency.
Q.92 Explain Go's garbage collection mechanism.
Go uses a concurrent garbage collector to automatically manage memory by reclaiming objects no longer in use. It runs in the background, minimizing pauses in the program.
Q.93 What are goroutines in Go, and how do they differ from threads?
Goroutines are lightweight, user-mode threads in Go that are managed by the Go runtime. They are more efficient than traditional OS threads, allowing thousands to run concurrently.
Q.94 How do you create a goroutine in Go?
You can create a goroutine by using the go keyword followed by a function call, like go myFunction().
Q.95 Explain the concept of channels in Go.
Channels are built-in data structures for communication and synchronization between goroutines. They allow safe data exchange and coordination.
Q.96 What is the difference between buffered and unbuffered channels?
Buffered channels have a capacity and can send multiple values before blocking, while unbuffered channels block until both sender and receiver are ready.
Q.97 How do you declare and initialize a slice in Go?
You can declare a slice using var or the shorthand := and initialize it using a slice literal, e.g., mySlice := []int{1, 2, 3}.
Q.98 Explain the difference between a map and a slice in Go.
A slice is an ordered collection of elements, while a map is an unordered collection of key-value pairs. Maps are used for fast lookups.
Q.99 What is the purpose of the defer keyword in Go?
defer is used to schedule a function call to run just before the surrounding function returns. It's often used for cleanup tasks.
Q.100 How do you handle errors in Go?
Go uses the built-in error type to represent errors. Functions that can return errors often return a value and an error. You can handle errors using conditional statements.
Q.101 What is the difference between a package and a library in Go?
A package is a collection of related Go source files, and a library is a collection of precompiled Go code that can be used by other programs.
Q.102 Explain the purpose of the init function in Go.
The init function is used for package initialization. It's automatically called before main() when a package is imported.
Q.103 How do you perform unit testing in Go?
Go has a built-in testing framework. You create test functions with names starting with Test, and you can run tests using the go test command.
Q.104 What is the purpose of the make function in Go?
The make function is used to create slices, maps, and channels with initial capacity and settings.
Q.105 Explain the concept of pointers in Go.
Pointers are variables that store the memory address of another variable. They are used to reference values indirectly, improving performance and enabling certain operations.
Q.106 How do you declare and use a pointer in Go?
You declare a pointer using the * symbol, like var ptr *int. You can access the value it points to using *ptr.
Q.107 What is a variadic function in Go?
A variadic function is a function that can accept a variable number of arguments. In Go, you define variadic parameters using ... before the parameter type.
Q.108 Explain the panic and recover mechanisms in Go.
panic is used to signal a runtime error, and recover is used to handle and possibly resume from a panic. They are typically used together in a deferred function.
Q.109 How do you import packages in Go?
You import packages using the import statement at the beginning of your Go source file, like import "fmt".
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